Unless I have the volume at 62, I don't get any sound at all, and then I get a very faint output.

Any ideas?

I think I found out why.

I cut out the RCA plugs to splice the cables. I think I should've just gotten RCA adapters.

Does anyone know the model for the speaker harness?

So I took a multimeter to my radio yesterday, there doesn't seem to be any resistance being output.

Could the issue be the unit itself?

I assume you've installed it in the 06 passat, right? If you used a harness w/ rca plugs then chances are all the negative speaker wires are tied together. This will cause a problem w/ the output. You need either a PAC C2RVW or Metra XSVI9003-NAV. These will have regular speaker wires for non-amplified (or in your case more likely, Monsoon system). Should fix the problem.

I assume you've installed it in the 06 passat, right? If you used a harness w/ rca plugs then chances are all the negative speaker wires are tied together. This will cause a problem w/ the output. You need either a PAC C2RVW or Metra XSVI9003-NAV. These will have regular speaker wires for non-amplified (or in your case more likely, Monsoon system). Should fix the problem.

I used the PAC harness. I shipped the unit back for a new one, let's see if the issue is fixed.

I tried plugging in a speaker directly to the rca outputs from the head unit and had the same sound issue.

So I got a new unit, same issue.

Anyone have any ideas?